The Dyerville Giant, one of the largest trees in the world. When this massive tree crashed to the ground in you could hear it for miles around. It sounded like a train wreck. ("Avenue of the Giants," Humboldt Redwoods State Park, California)
During a summer vacation to central California, one of the caches I found was inside an olive tree similar to this one. Living on the east coast, I had never seen an olive tree before and I thought they looked so cool.